Interactions of umami with the four other basic tastes in equi-intense aqueous solutions

Previous research has shown that the addition of equi-intense concentrations of taste compounds leads to mixture suppression, with sweetness being the least suppressed taste while being the strongest suppressor of the other taste stimuli. However, perceived intensity of umami (savoury) within complex mixtures is less defined. Since maintaining savoury taste of foods at reduced salt levels is a growing need, this study aims to investigate the role of umami in complex taste systems. Initially the concentrations of single tastants were adjusted until a trained sensory panel rated them as equi-intense using general labelled magnitude scale (gLMS). In order to evaluate the impact of umami taste on other tastes, and vice versa, three sample sets were prepared as binary and quinary systems. The first two sets utilised monosodium glutamate (MSG) as the umami tastant; one set without balancing the sodium level in MSG (sodium unbalanced) and another set accounting for it by the addition of sodium at an equivalent molarity to all but the umami single tastant solution (sodium balanced). The third set used monopotassium L-glutamate monohydrate (MPG) as the source of umami to overcome the confounding influence of sodium. All samples were rated by trained sensory panellists. The results of the three studies conclude that umami taste does not enhance or suppress the perception of any other taste in binary aqueous taste systems (p > 0.05); whereas sweet, salty, sour and bitter significantly suppress the perception of umami in both binary and quinary systems (p < 0.05).